Vibrating screen



July 8, 1941. E CHAMBERLAKN 2,248,042

VIBRATING SCREEN Filed Jan. '19, 1959 I'll Patented July 8, 1941 VIBRATI N G SCREEN Leon E. Chamberlain, Oakfield, N. Y., assignor to Alfred E. Fielding, Buffalo, N. Y.

Application January 19, 1939, Serial No. 251,769

2 Claims.

This invention relates to improvements in vibrating screens, particularly those of the kind which, owing to the fine mesh of the screening cloth or the nature of the material to be screened, or both, have a tendency to blind.

The principal object of the invention is to provide a screen which'is so designed that any tendency to blind, regardless of the cause, is counteracted, this object contemplating the association with the conventional actuating mechanism of means for imparting supplemental impulses to the screening cloth to clear the openings of material which might otherwise obstruct them.

A further object is to provide improvements of the character generally described which may be either incorporated in the screens as originally constructed or which may be applied to ex isting screens as an attachment.

A still further object is a screen wherein provision is made for varying the intensity of the impulses produced by the supplemental vibrating means.

A still further object is to provide a screen which is so constructed that the impulses of the supplemental vibrating means are transmitted substantially uniformly throughout the screening areas.

A still further object is to provide a novel design and arrangement of the parts of the screen, whereby simplicity and economy in construction are insured.

The invention is illustrated in the accompanying drawing in which:

Figure 1 is a side elevational view of a vibrating screen embodying the features of the invention. Figure 2 is an enlarged transverse vertical section taken along line 2-2 of Figure 1. Figure 3 is an enlarged fragmentary section taken along line 3-3 of Figure 2. Figure 4 is a detail view of one of the impulse producin elements of the supplemental vibrating means.

The features of the invention are illustrated, by way of example, in connection with a screen having a live frame 5 and a base frame I, the former including side plates 8 and 9 between which upper and lower screening decks l and M, respectively, are secured. The base frame 1 includes longitudinally extending members l2 which carry bearings I 3. The latter provide a mounting for an actuating shaft H which passes through the side plates 8 and 9 substantially centrally of the live frame. Springs I which are located at opposite ends and on each side of the live frame act against the members I 2 and housings l6 which are carried by the side plates 8 and 9 to maintain the live frame in the proper position and at the same time support a part of its weight. The actuating shaft I4 is enclosed in a tubular housing II, it being understood that those portions of the said shaft upon which the live frame is mounted are, in accordance with conventional practice, eccentric with relation to those portions mounted in the bearings l3. Hence a rotary movement of the actuating shaft will cause the live frame to move in a'circular path, the entire movement of the live frame be ing in a vertical plane. During such movement of the live frame it is prevented from canting with respect to a predetermined normal position, whereby all portions of the live frame movein circular paths of substantially the same diameter. The actuating shaft is driven by a suitable motor (not shown) which may be mounted upon the base frame and connected by a suitable belt to one of the pulleys I8 formed or provided upon the opp site ends of the said shaft, the latter preferably also carrying flywheels 19 which are adapted to counterbalance the centrifugal forces set up during operation of the screen. So much of the screen as has been described is of conventional design and has, therefore, been illustrated only generally.

In accordance with the invention, means is provided for imparting supplemental vibrating impulses to the live frame 6 in order to clear the screening openings of material which might otherwise obstruct them. The said means includes angle bars 20 which are suitably secured to the undersides of the longitudinally extending base frame members [2. Each of the said angle bars, as illustrated, carries a plate 2| which in turn carries a bracket 22, the angle bars 20 and the horizontal portions of the brackets 22 being formed with aligned guide openings 23 for impact elements 24. The latter are mounted for axial movement. Compression springs 25, which are arranged around them, abut at their lower ends against the angle bars 20, while at their upper ends they abut against washers 26 applied to the respective impact elements below their guide brackets 22 and held against upward displacement by stop pins 21 applied to such elements.

The impact elements 24 are shown as cooperating with cross bars 29 of the live frame. The said cross bars are located at opposite sides of, and at substantially equal distances from, the actuating shaft while the impact elements are located directly under the 'cross bars at points substantially midway between the side plates of the live frame. The impact elements are supported so that during movement of the live frame through the upper portion of its path of travel the cross bars 29 move out of contact with and 1 away from them and permit them, under the influence of the springs 25, to move to theupper limits of their ranges of movement, while during movement of the live frame toward the lower portion of its path of travel the said cross bars strike the impact elements to impart supplemental vibrating impulses to the live frame. The springs ing decks. As they travel at right angles with" respect'to the said deck-s, they are particularly effective in clearing the screening openings. The

, intensitywof theimpulsesis dependent, among 1 otheifir factors, upon=thespeedof the live frame, thefweighti of the-impact elements and the compression of the springs 25. It -may be -varied,

th,erefore,--by-varying the compression'of' the said springswTo: this end each of the elements 24 is I 25 permit the impact elements to yield when they j are struck in the manner described and during the remainder of the movement of the live frame through the lower portion of its path oftravel.

The impulses thus produced" are sharp and. are Z transmitted through the live frame toth'e' screen- Y the adjoining portion of the screen frame, and a compression spring applied to said bar for yieldingly resisting its. downward displacement and imparting smart up-thrusts thereto to supplement the normal vibrations of the screen frame, said impact bar being spaced from the screen frame during a part of its gy ating path formed with a; series of spacedholes or bores (F i'gur e-4 )-to provide for adjustment of the pins ZIc-to enable compression-of the springs 2'5 to thewdesired-degree.

From-'the foregoing it will be apparent that the-:arrangement of thejimpact elements in the manner *described has theadvantage that they counteract one another insofar asany tendency to rotate'the live frame 'upon the actuating shaft 3 is concerned; In 'this--connection it is to 'be understoodthat the use of a single impact element oneach-side of'the actuating shaft, as shown, isv byway of illustrationonly and-that theinventionwcontemplates the employment of various numbers and arrangements of the said elements as circumstances may require.

I claimias my invention:

1; In :a vibrating screemra base frame, a screen frame cresilientlycmounted' on said base frame,

and being engageable therewith during another part of such path.

2.. In .a vibratingiscreen; a base frame, a screen frame'resiliently m'ountedon said base frame, means for positively gyrating said screen frame relative to said baseframejthrougha" fixed path lyingin a vertical plane; and means for, imparting supplemental vibrations-to said screen frame comprising a bracket attached to said base: framebelow said screen frame; said bracket having substantially-horizontallyedisposed, upper and lower portions having alinedguide'bpenings' therein, an

impact :bar :guided in said openings and extending at its upper endi'freely above the upper portionof said bracketzfor thrust engagement with the screen deckgand'ancompression spring'coiled about said rbar and: abutting "at its lower end against the'lowernportion of the bracket,the

upper end of the springabutting'against a washer applied to the barbelow:the upper portion of said bracket; saidlmeans bein'grso positioned that said screen framei'is out of contact With said impact bar in the upper portion of said path," and strikes said impact bar duringmoti'o'n toward 7 the lower portion of .sa'id path.

E. CHAMBERLAINJ 

